Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
To ensure that wind power remains a viable energy source, efforts have been made to increase energy outputs by modifying the size, configuration and capacity of wind turbines. One such modification has been to include a tip feature, such as a winglet, at the tip of each wind turbine rotor blade. Generally, winglets can be employed to improve the overall efficiency and performance of a wind turbine. Winglets may also be installed on rotor blades to reduce the overall diameter of the wind turbine as well as to reduce noise emitted by the blades. Further, winglets may also provide an increase in the power coefficient of a wind turbine and, thus, reduce the cost of energy generated by the wind turbine.
It is generally understood that suction side winglets are more efficient than pressure side winglets. However, for wind turbines having rotors upwind of the tower, the use of suction side winglets can be very problematic. Specifically, installing a suction side winglet on a rotor blade reduces the distance between the tip of the rotor blade and the tower. Such a reduction in tower clearance can dramatically increase the risk of one or more of the rotor blades striking the tower, which can be a very costly event requiring considerable downtime to repair and/or replace damaged components. Catastrophic tower failure is also a possible outcome of a tower strike.
Accordingly, a method for using site specific wind conditions to determine when a tip feature, such as a suction side winglet or a tip extension, may be installed onto a rotor blade in order to increase the overall performance of the blade without significantly increasing the risk of a tower strike would be welcomed in the technology.